Construction of electromagnets.



H. LACY.

CONSTRUCTION OF ELECTROMAGNETS.

APPLICATION FILED AUG. 31, 1906.

928,136. PatentedJu1y13, 1909.

2 SHEETS-BHBBT 1.

i To all whom it mag wncem:

UNITED STATES PATENT curios: 7

HOWARD LACY, F CARSHALTON, ENGLAND.-

CONSTRUCTION ELEGTBOMAGNETS:

Specification of Letters Patent. Application filed August 31, 1906. Serial No. 332,845.

Patented Jul is, 1969.

Be it known that I, HOWARD beer, a subject of the King of Great Britain,'residing at Kelvin, Camden Road, Carshalton, in the county of Surrey, England, engineer, have invented certain new and useful Improvements in the Construction of Electromagnets, of which the following is a specification.

. This invention has reference. to the type of electromagnet which formed the subject matter of Letters Patent of Great Britain granted to Dugald Clerk, on a communication from myself, Louis F. Johnson and \Valter J. Slacke, dated September 24th 1895, No. 17790 and is designed to rectify certain defects and omissions presented by the construction therein described, which defects were inimical in practice to the'working of that invention. Figure 1 shows by a' plan view a pair of cores a with their yoke b and the four spreaders c, c, 0, c, andtheir four diamagnetic plates 6, e, e, e, the-Spreaders and plates of the left'leg of the core being in section.-

' Fig. 2 shows a plan of a pair of helices wound upon the pair of cores shown by Fig; 1,'with the one spreader andone plate 6 of the left'leg in section. *Fig. 3 is a back view of Fig. 1 and Fig.2. Fig. 4 is a front view of Fig. 2 and Fig, Fi 5 shows diagrammatically" a method 0 winding.

helicesadapted for low Voltages, and is a section of one leg of themagnet d, showing the course taken by the wires '0, s, t, in the left leg of the magnet, with the core'a and. interposed insulation's z, i, 2', et cetera. The

wire 7' is started right handed upon the one leg and the corresponding wire on the op-- posite leg 'is wound starting left handed.

In Fig. 5 and in the left leg of the magnet Fig. 2 the ingoing ends of the wires 1', s, t, are respectivelymarked l, 3, 5, while the outcoming ends of these wires are respectively marked 2, 4, 6. Fig. 6' is a plan in partial section of Fig. 5 and to the same scale.

The right leg of the magnet Fig, 2 is arranged with its gradations of wire in the.

' same order as in the left leg of the magnet but the windings are in the opposite directlon.

As an approved construction designed to carry out my invention '1 would give the followin formula for use in dealing with commercial or lower voltagese- The core, a is made of bunches of soft bundle it is placed upon.

wrought iron wires, cut into even lengths and clamped'on the ends of the poles by spreaders- ,0 of twice the diameter of 'the v This clamping should be done so firmly as to bring the spreader-s 0 and the wires (1 at the ends into the closest possible contact. The Spreaders or washers, 0 should also be of soft wrought iron, and the diameter outside should, as already mentioned, be twice the diameter of the bundle of wrought iron wire on which 1 the spreader is to be firmly clamped" This spreader is bored out centrally so that the bundle of wire passes clear through it and when finished the ends of all the wires are flush with the front faces of these spreaders.

"The 'plates,.e, e, to hold the heliz'rof wires to be wound on this core may be made-of brass, v'ulcanite or other suitable substance, but preferably of a high electrical conduct" ingor diamagnetic material aluminium being convenient; such platesbeing bored out.

centrally and slipped on the bundle of wires, or core, a before clamping on the second spreader c and these plates fit firmly against the" back of the Spreaders. The plates at the ends of the cores which willbe the back end I of the electromagnet have small holes f, f,

.bored through them and bushed or lined with insulating material through which the ends 2, 4,6, and commencemcnts 1, 3, 5,0f

the various sized wires constituting the helix l wound on the cores are brought out for purposes to be described later. These plates 6, e, when made, of diamagnetic material aid in concentrating'thelines of force around the spreaders.

The yoke, 79, is a plate of soft wroiight ironand the best effect generally is attamed by making it equal in size (in square inches) to one half the length of one of the cores In winding the helix: First carefully and thoroughly insulate the core a then wind the spools of the magnet in layers, each layer of winding'being carefully and eifectlvely 1nsulated from the layer above and the layer below it in the construction, the size of winding wire I furthermore vary in thickness, forming the layers next adjacent to the core of heavier wire than those superimposed thereon. The component wire forming each successive set of layers from the core to the circumference is of diminished thickness, and the thickness of wire of each set of layers 'is graduated so as to bring in suflicient re- .sistance at each change of grade of .wire

without producing any excessive retardation of current, the outermost layers being neces sarily of the finest grade.

The gradations of thicknesses of wires are varied and adj usted to circumstances, the windings always increasing in number -of-layers as they decrease in diameter of-component wire. The

- wires-of the windings are reversed in the direction of their winding at the end of every second layer, the'direction of winding of two layers being arranged say, in the direction known as clockwise and the next two layers in the opposite or contra-clockwise direction and so on alternately.

As a practical illustration of actual manufacture supposing direct current to be the to receive wires as hereafter explained. As

many wires as possible are crowded within a .predetermined area by clamping them with heavy pressure near one end of the bundle and on this end is placed a spreader c heated and expanded, using such slight force as may be requisite. As soon as the spreader has shrunk the clamp is removed and the rigid hold on the wires is then taken up' by the spreader.the ends of wire extending to inch beyondit. The bundle at is now threaded through the hole in a plate e, an ranging the best finished faceof each plate e in contact with the back of the spreader 0.

Now make up the other end of core, clamp it as before, apply the second plate 6, the secf the use'of hydraulic pressure the process is- 0nd spreader heated and then allowed to cool and shrink .and remove clamp, but with simplified. The surplus lengths of wires extending through the spreaders having been trimmed off flush leave a perfectly fiat and even surface at each end. The inside faces of these spreaders should be cleaned and each plate, 6 set evenly against them.

The wires used in winding the helices hereafter referred to as Nos. 14, 16, 18 and so on respectively are so designated to indimencement.

cate their relative diameters.' They are each formed of double cotton covered copper" magnet Wire and 'the flexible cotton covered copper wire or the like ends say 12" long re ferredxto as being soldered on at the begin ning and ending of each size of wire, are carefully adjusted so that their carrying capacity is equivalent to the wire they are soldered to. The beginnings and endings of each size of wire after being brought or passed through the holes at f are fastened t prevent slipping of the windin s.

It is essential to the success 0 this invention that before commencing to wind the second layer of wound wire the first layer should be efliciently insulated as by the application of 'shellac and thick insulating paper, or other suitable insulating material, and thereafter each and every layer of wound wire must be similarly insulated from each adjacent layer.

At each-ibending back of any given size of wire on itself to form a light strong string or the like binding tie is applied givingone or two turns close to the plate 6 to keep the wire from slipping out of place upon the direction of wind being reversed.

I After placing the core a (Fig. 5) in a lathe or the like, and a platee in close contact with each spreader 0 the core a is wrapped tightly. with insulating material covering the core wires a very carefully, commence to wind thereon wire 1", say No. 14, having first affixed the flexible end 1 referred to, putting it through an end hole 7- allowing enough flexible end inside plate 6 to go once around the core, wind on evenly and closely across to the other plate 6 and apply insulation 2'. The Winding is now continued the latter still moving in the same direction as when winding the first layer. Winding evenly and closely coming back to the starting point; now having laid two layers again apply insulation i. This wire 1' is cut off and the said flexible end soldered on and the end is passed out through a hole at f and fastened. Next take No. 16 wire (8 Fig. 5) and solder on a flexible end 3 pass it through a hole 7. Reverse the motion of the lathe, so that the winding proceeds in the opposite direction to what it was when winding on the first two layers, wind evenly and closely up to the plate 6 and insulate at 2', then continue winding back to point of commencement and again insulate. Here bend the wire back on itself, fasten, reverse the motionof the lathe, and wind evenly to the end, and insulate; c011- tinue winding back to the point of com- Cut off wire, add flexible end 4: and pass it through hole at 7. Take now No. 18 wire t add a flexible end 5 pass I through hole at 7, reverse the motion of thc lathe to the direction it was last moving, and wind evenly to the end, insulate and went.

again insulate.

'umn mencement.

wind back to commencement, bend 1 wire end, insulate and wind back to the point of back on itself and fasten. Insulate last layer. Reverse motion of the lathe and wind evenly to the end, insulate and wind back to the point of commencement; again insulate. Bend wire back on itself and fasten. Reverse the motion of the lathe wind evenly to the end, insulate, and wind back to point' of commencement. Cut off wire and add flexible end 6 pass it through hole at f and fasten. Should it-be desired to continue the winding of such a helix, as that just described, in'order' to'increasc its general efliciency,'by further developing it, using a finer gage of wire which would be No. 20 gage in this case, and the number of layers should be eight instead ofisix layers as in the preceding grade of wire, and correspondingly if the efficiency is further enhanced by a further winding which would be No. 22 in this case the number of coilshelix so as to be better adapted for r-hlghe r voltages than that just described I proceed as follows :.Havmg prepared a core and applied the two first layers of coarsest winding 1" (as in the previous instance) I then bend the wire 1 back on itself-and fasten.

The motion of the lathe is now reversed, and

the winding evenly continued to the other.

end, again insulate at i and the winding 1s continued with the lathe in the" same direction= as for the last layer and insulated. This wire '1' is cutoff and the saidflexible end soldered on and the end 2 is passed out through a hole at f and fastened. Next take N0. 16 wire, (a Fig. 5) and solder on a'flexible end 3 pass it through a hole f, reverse the motion of the lathe, so that it revolves r in 'the same direction as when Winding on thcfirst t layers 7' windevcnly and closely up to the plate a and insulate at- ?1 then con tinueback to point of commencement and wind evenlyto the end and insulate;'continue windingrbaek to point of commence l-lere bend the Wire back on itself;

fasten and insulate, revcrsethe lathe wind axible end at andpass it through wire 2?, add. a flexible; end 5 pass through hole at f, reverse the motion of the latheto the direction it. was last moving, and wind evenly to the end insnlate'and wind back to Bend wire back on' itself Reverse and fasten? Insulate lastlayer.

motion of the lathe and wind evenly to the Here bend the'wire back, on itself reverse the motion of the lathe, and

commencement, again insulate' Bend the insulate and wind back to point of commencement, insulate and bend wire back on itself and fasten, reverse the 'motion of the lathe wind on evenly to the end, insulate again and wind back topoint of commencement, out 01f wire and add flexible end 6175- pass it through hole at f and fasten. Now take No. 20 wire, solder on a flexible end as before and pass it through ahole at, f and insulate; reverse motion of the lathe and wind on evenly to the end and insulate, wind back topoint of commencement. Bend wire back on itself fasten and insulate, reverse motion of lathe and wind on an even layer,

insulateand wind back to the point of comon itself and fasten, reverse the lathe, wind on an even layer, insulate and wind back to point of commencement, insulate and fasten, reverse lathe'and wind on evenly to the end,

insulate, wind back topoint of commencement, insulate. Bend wire back on itself and fasten. Reverse lathe and wind on evenly to the end insulate, and now wind on evenly the last layer to the point of comr'nencement. end]? passsameout through a hole at f, and

securely-fasten.- v a To further develop sucha magnet for certain purposes, where such an efliciency might be called, using a finer gage of wire which would'be No. 22 gage in this case, and iml number of layers added twelve as against ten layers in the preceding set, and otherwise strictly following the formula as to reversals, relative capacities of :wires, inter- ,105 spaeing 'of insulatlon at each :layer, and

so on. p The beginnings and endings of the various grades of wire I bring out of the end of the magnet so that .various combinations may 11.0 v

be made as between the gages by which the current can be sent through all the wires suecessively 'or through two or more sizes jointly By these means I can attain the following series, all multiple, series mult1ple,mult1ple'- series, multiple series multiple, shunt series,

shunt multiple, shunt multiple series, shunt series multiple, and so on, the more various sized wires on'the electromagnet the more combinations and such other variations of combination as will be obvious to a skilled v electrician. By these and similar combinations among other advantages facility for" the adaptation of such magnet-to variations of. current of electrical energy employed are obtainable. v I

' The length of the yokefshould be equal 1n measurement to half the length of one leg of the magnet divided by the diameterof the;

Cut off wire, adda flexible 95 variations of combinations :-'all I 115 l 25 tions. In this way the speed of the motor 1. structed as hereinbefore described will be found useful for employment as the primaries in inductioncoils, as well asfor various other applications of the electromagnets.

Electro-magnets have been constructed in accordance with the present invention and used in connection with induction coils, motors and other electrical apparatus, and such magnets have been found to possess the advantage of a material reduction in the cost of production, due to the reduced amount of wire and the decrease in the size of the magnet in order to obtain given results, and the necessity of using a rheostat in connection with motors and similar apparatus is obviated, and in its stead may be employed a simple switch or controller for connecting the several windings in different combinamay be readily controlled and an economy in current consumption as distinguished from magnets which require the use of a rheostat for introducing external resistance in the circuit, the excess of electrical energy being in those cases converted into heat and thus wasted. 1

Having now particularly described and ascertained the nature of my said invention,

and in what manner the same is be performed, I declare that what I claim is 1. An electro magnet comprising a core, groups of even numbers of layers of wire disposed thereon, the diameter of the wire composing each successive group diminishng progressively and the number of layersin each successive group increasing in direct arithmetical progression, and insu ating material between the'core and its adjacent winding and between successive layers of the series, whereby the resistance of the winding increases in definite proportions through the electro magnet.

2. An electro magnet comprising a core,

windings composed of superimposed groups of even numbers of layers of Wire disposed thereon, the diameter of the Wire in each successive group decreasing progressively and the number of layers in each successive group increasing in direct arithmetical progression, the direction of the winding being reversed at the end of every'second layer and all the layers being insulated from one another.

3. An electro magnet comprising a core, windings composed of superimposed groups of even numbers of insulated layers of Wire disposed thereon, the diameter of the W re in each successive group decreasing progressively and the number of layers in each successive group increasing in direct arithmetical progression, the direction of the Winding being reversed at the end of every second layer and'the free ends of the wire composing each group being brought out at the same end of the magnet for the purpose of being connected up in accordance with any desired combination, substantially described."

4. An electro-magnet comprising a core, windings applied thereto, the wire composting said windings diminishing in "sizeprogressively in a direction from the core out- Wardly and increasing in the number of layers in definite progressive order with each reduction in the size of the wire whereby the resistance of the windings will be increased in definite degrees from the core outwardly, the direction of the windin being reversed at the end of every secon layer and the beginnings and ends of each size of wire be ing exposed at the exterior of the magnet whereby such windings may be connected in different combinations, and an efficient body of insulating material interposed be, tween the layers of every winding.

In testimony whereof I have hereunto set my hand in presenceof two subscribing witnesses.-

' ERNEST JoHnHILL,

T. J. OsMAN. 

